Sear-actuating means for machine guns



Feb. 19,- 1946. c. G. SWEBILIUS 2,395,023

SEAR-ACTUATING MEANS FOR MACHINE GUNS Filed April 22, 1944 2 Sheets-Sheet 1 /a Maj Q 7 0 flw/z/vro/v CARL G. SWEBILIUS A T TO RNEYS Feb. 19, 1946. c. ca. SWEBILIUS SEAR-ACTUATING MEANS FOR MACHINE GUNS Filed April 22, 1944 2 sheets -sheet 2 Patented Feb. 19, 1946 S EAR-ACTUATINGGMEQN S FOR MACHINE UN Carl G. Swebilius, Hamden, Conn, assignor to The High Standard Manufacturing Company, Hamden, Conn, a corporation of Connecticut Application April 22, 1944, Serial No. 532,232

Claims.

The present invention relates to improvements in machine guns and relates more particularly to improvement in sear-actuating means therefor. The sear-actuating means of the present invention is adapted for use in connection with machine guns of the so-called Browning type, which type of machine gun is disclosed in detail in Browning, United States Patent No. 1,628,226, dated May 10, 1927.

It may here be explained that in machine guns of the Browning type above referred to, a reciprocating sear-actuator is employed for moving the sear to thus release the firing-plunger to effect the discharge of the machine gun. As heretofore. constructed, however, the sear-actuator of the type of machine gun above referred to is susceptible of breakage especially when attempts are made to operate machine guns (especially those of ,.50-caliber and larger), at speeds materially in excess of eight hundred rounds per minute.

As will more fully hereinafter appear, the present invention relates to a construction and arrangement of parts, whereby the sear-actuator is reversible for movement from either side of the breech-bolt, and is so constructed and arranged as to be firmly confined within a predetermined stroke, but readily releasable for shifting to a diflerent position or for removal and replacement.

One of the objects of the present invention is' to provide a machine gun with superior means for actuating the sear thereof to enable the machine gun so equipped, to operate satisfactorily at high speed.

Another object of the present invention is to provide a machine gun with a superior construction and arrangement of parts, whereby the searactuator will effectively shift the sear to release the firing-plunger, and of such character as to operate smoothly and reliably and to withstand the shock of high-speed operation for long periods of time.

With the above. and other objects in view, as will appear to those skilled in the art from the present disclosure, this invention includes all features in the said disclosure which are novel over the prior art and which are not claimed in any separate application.

In the accompanying drawings, in which certain modes of carrying out the present invention are shown for illustrative purposes:

Fig. 1 is a broken top or plan view of the rearportion of a breech-bolt equipped with an improved sear-actuating means embodying the present invention;

Fig. 2 is a view thereof in side elevation;

Fig. 3 is a view of the breech-bolt in rear elevation;

Fig. 4 is a vertical central-longitudinal sectional view taken on the line 4-4 of Fig. 1;

Fig. 5 is a broken transverse sectional view taken on the line 5-5 of Fig. 2 but omitting the firing-plunger} Fig. 6 is a view in rear elevation of the breechbolt stripped of its movable features;

Fig. '7 is a detached perspective view of the sear-actuator but on an enlarged scale; and

Fig. 8 is a view mainly in side elevation and partly in central-longitudinal section of the retaming-plunger, but on an enlarged scale.

In the accompanying drawings, is shown the rear-portion of a breech-bolt generally designated by the reference character It], and which is formed centrally in its lower-portion with a longitudinal passage II in which reciprocates a firing-plunger 12. In the usual manner of machine guns, the said firing-plunger I2 is urged forwardly by spring-means (not shown), and is provided at its rear end with a cocking-hook l3 (Fig. 4) extending downwardly and adapted to have its forward-face releasably engaged by the rear-face of a cocking-hook l4 formed on the lower-portion of a vertically-reciprocating sear generally designated by the reference character 15.

The sear l5 above referred to, reciprocates in a vertical channel l6 formed in the rear-portion of the breech-bolt and intersecting both the upper and rear surfaces thereof. In each of its respective opposite side-Walls, the channel [6 is formed with one of two opposed vertical guide- Ways l'I-l'l respectively receiving with a sliding fit, one of two opposite vertical guide-ribs Ill-I8 formed respectively on the opposite sides of the sear l5. The sear I5 is normally urged upwardly in a direction required to engage its cocking-hook I4 with the, cocking-hook l3 of the firing-plunger l2 by means of a helical sear-spring H) which is interposed between the upper-portion of the bottom-Wall 20 of the vertical channel l6 and the upper face of the sear l5. On its rear face, the sear i5 is formedwith anactuating-lug 2i having a wedge-shaped upper-portion providing two cam-surfaces 22 and 23 respectively sloping downwardly-and-laterally from their central point of junction.

Coactingwith the cam-surface 22 on the upalso intersects, at its respective opposite ends, the left face (as viewed in Fig. 3) of the breech-bolt V and the adjacent side of the vertical channel It therein. Transversely in line with the horizontal channel 25 just referred to, is a similar horizontal channel 27 which, however, is located on the opposite Side of the vertical channel I6, as clearly a 4 shown in Figs. 3, 5 and 6.

In each of its respective upper and lower walls, the left horizontal channel 26 is formed with one of two opposed guideways 28-28. Similarly, the right horizontal channel 21 is formed in its upperand lower-walls respectively with one of two opposed guideways 29-29.

The plate-like sear-actuator is provided on its upper and lower edges respectively with one of two parallel guide-ribs 30-30, adapted to extend, with a sliding fit, either into the horizontal guideways 23-28 of the left channel 25 (as is shown in theedrawings) or into the horizontal guideways 29-29 of the right channel 21 in the breech-bolt Hi, all as will more fully hereinafter appear.

The sear-actuator 25 is formed substantially centrally with a longitudinal limiting-slot 3|, which is adapted to receive a cylindrically-contoured retaining-pin 32 formed integral with, and projecting rearwardly from a cylindrically-contoured retaining-plunger 33. In the particular instance shown in the drawings, the retainingplunger 33 just referred to, is mounted for reciprocation in a retainer-socket 34, formed in the breech-bolt Ill and intersecting the forwardor inner-wall of the left horizontal channel 26 therein. As will more fully hereinafter appear, the retaining-plunger 33 may be shifted for reciprocating movement into a retaining-socket 35 corresponding to the retainer-socket 34, but located on the opposite side of the vertical channel I5 and intersecting the forwardor inner- Wall of the horizontal channel 21 before referred to.

In its forwardor body-portion, the retainingplunger 33 is formed with a forwardly-opening spring-receiving pocket 36, which receives a helical spring 31 seated against the inneror frontwall of the retainer-socket 34, and exerting a constant but yielding effort to urge the retainingplunger 33 rearwardly to maintain the retainingpin 32 thereof in the limiting-slot 3| in the searactuator 25. The rearward movement of the retaining-plunger 33, under the urge of the spring 31, is limited by the engagement of the rear face of the body-portion of the said retaining-plunger with the forward or inner face of the sear-actuator 25.

As is well understood in the art, the sear l5 may be depressed from the position in which it is shown in the drawings, to release the firingplunger l2. To effect this downward movement of the sear l5, any suitable firing device in the machine gun may be utilized to engage the outerend of the sear-actuator 25 and force the same inwardly, to thus cause the slopingcam surfac'e 24 at its inner end to slide on the cam-surrace-zz of the actuating-lug 2| of the said sear and depress the said sear [5. The downward movement of the sear |5 will disengage the cocking-hook l4 thereof from the cocking-hook l3 of the firingplunger l2, thereby permitting the said firingplunger to snap forwardly in the manner usual in machine'guns'to efiect the discharge of the latter.

Normally, the sear-spring |9 will serve to maintain the sear l5 in its upward position, thereby causing the cam-surface 22 of the sear to cam the sear-actuator 25 outwardly into the position in which it is especially well shown in Fig. 3. This outward movement of the sear-actuator 25 will be limited by the engagement of the inner end of its limiting-slot 3| with the retaining-pin 32.

-Thelimiting of---the outward movement of the sear-actuator 25 by the retaining-pin 32 will, in turn; limit the upward movement of the sear l5 when the firing-plunger |2 isin its forward position.

Should it be desired to remove the sear-actuator 25 or its equivalent for inspection, repair, replacement or the like, the pointed end of a bullet or other suitable tool may be applied to the rear end of the retaining-pin 32, to thereby force the retaining-plunger 33 forwardly into a retired position sufficiently to have the rear or outer face of the said retaining-pin 32 clear the forward or inner face of the'sear-actuator 25. Fol.- lowing this operation, the sear-actuator 25 may be slid outwardly and removed, whereupon the sear I5 is free of restraint by the sear-actuator 25 and may be removed upwardly provided, 7 of course, the firing-plunger l2 and other interfering features are first cleared out of its path.

Should it be desired to effect the discharge of the firearm from the right side of the breech-bolt, the sear-actuator 25 may be removed in the manner above described, following which the retaining-plunger 33 and its spring 3'! may be removed from the retainer-socket 34 and transferred into the retainer-socket 35 on the opposite side of the vertical channel It. tor 25 may now be turned over and installed in the horizontal channel 2! at the right of the vertical channel It in such manner that its camsurface 2'4 will engage with and conform to the cam-surface 23 of the sear l5. In effecting the insertion of the sear-actuator 25 into either of the horizontal channels 26 or 21, the retainingplunger 33 in the selected one of the saidchannels will beretired manually to permit such installation, and when the sear-actuator 25 is moved inwardly sufiiciently, the retaining-pin 32 of the retaining-plunger 33 will automatically snap into the limiting-groove 3| to thereby discharge its limiting-and-retaining function} By means of the constructio and arrangement of parts above described,'wherein the sear-actuator is short withminimum mass and withnege ligible central overhang, machine guns; may be operated at very high rates of speed without, damageto either the sear-actuatoror thelsear,"

teristics of the invention, and the present em-- bodiments are; therefore'fto 'be consideredirf all respects as illustrative and not restrictive, and

all changes coming within the meaningand The sear-actuafrom; a scar mounted for vertical reciprocation V in the vertical sear-receiving channel in the said breech-bolt; a sear-actuator engageable with the said sear to depress the same and mounted for horizontal reciprocation in one of the two horizontal actuator-receiving channels in the said breech-bolt, the said sear-actuator being constructed and arranged to interchangeably fit into either of the said horizontal actuator-receiving channels and having a horizontal limitingslot; a retaining-plunger mounted for reciprocation in one of the two plunger-receiving sockets in the said breech-bolt adjacent the said searactuator and constructed and arranged to interchangeably fit into either of the said sockets, the said retaining-plunger having a portion extending into the horizontal limiting-slot in the said sear-actuator to limit the movement thereof; and spring-means yieldingly holding the said portion of the retaining-plunger in the horizontal limiting-slot of the said sear-actuator.

2. Sear-actuating means as defined in claim 1 and having the said sear-actuator suificiently short to fit in only one of the horizontal actuatorreceiving channels in the breech-bolt when the sear-actuator is in its retired position.

3. Sear-actuating means as defined in claim 1 and having the said spring-means accommodated in the socket in which the retaining-plunger is located.

4. Sear-actuating means for machine guns, including in combination: a machine-gun breechbolt having a vertical sear-receiving channel in its rear face and also having in its rear face two substantially-corresponding horizontal actuatorreceiving channels respectively located on the opposite sides of the said vertical sear-receiving channel, the said breech-bolt being formed with two substantially-corresponding retainer-receiving pockets respectively intersecting one of the two horizontal actuator-receiving channels in the said breech-bolt and extending forwardly there from; a sear mounted for vertical reciprocation in the vertical sear-receiving channel in the said breech-bolt; a sear-actuator engageable with the said sear to depress the same and mounted for horizontal reciprocation in one of the two horizontal actuator-receiving channels in the said breech-bolt, the said sear-actuator being constructed and arranged to interchangeably fit into eitherpf the said horizontal actuator-receiving channels and having a horizontal limiting-slot; a retaining-plunger mounted for reciprocation in one of the two plunger-receiving sockets in the said breech-bolt adjacent the said sear-actuator or and constructed and arranged to interchangeably fit into either of the said sockets, the said retaining-plunger having a forwardly-opening springreceiving recess and provided at its rear end with a rearwardly-projecting retaining-pin extending into the horizontal limiting-slot of the said searactuator to limit the movement thereof; and a helical spring fitting into the forwardly-opening recess of the said retaining-plunger and into the adjacent one of the retainer-receiving pockets in the breech-bolt and yieldingly urging the said retaining-plunger rearwardly.

5. Sear-actuating means for machine guns, including in combination: a machine-gun breechbolt having a vertical sear-receiving channel in its rear face and also having in its rear face two substantially-corresponding horizontal actuatorreceiving channels respectively located on the opposite sides of the said vertical sear-receiving channel; two retainer-holding means carried by the breech-bolt and respectively located on the opposite sides of the said sear-receiving channel and respectively adjacent one of the said actuator-receiving channels; a scar mounted for vertical reciprocation in the vertical sear-receiving channel in the said breech-bolt; a sear-actuator engageable with the said sear to depress the same and mounted for horizontal reciprocation in one of the two horizontal actuator-receiving channels in the said breech-bolt, the said sear-actuator being constructed and arranged to interchangeably fit into either of the said horizontal actuator-receiving channels; and retainingmeans constructed and arranged to interchangeably engage with either of the two said retainerholding means and coacting with the said searactuator to limit the movement thereof.

CARL G. SWEBILIUS. 

